Cable Force Identification of Stayed Cables Considering the Interference of an External Damper

As the main form of modern large-span bridges, the cable-stayed bridge is a key hub of the urban transportation network. Stayed cables, as the core load-bearing components of the bridge, bear and transmit huge loads. Accurate identification of the cable force is crucial for the assessment of bridge condition assessment, safety warning, operation, and maintenance. To suppress the large vibration of the cables, external dampers are commonly used to improve their dynamic performance. However, the difficulty in precisely obtaining damper parameters and the time-varying, nonlinear characteristics of the actual damping forces pose significant challenges to traditional cable force identification methods. To address this issue, this study solves the cable vibration equation based on the coordination condition of the damper support position and establishes the cable–damper transmissibility function (CDTF). A cable force identification method for the cable–damper system (CDS) to overcome the interference of the damper is proposed. The accurate identification of the cable force can be achieved by measuring the vibration responses of the free segment of the cable and the support position of the damper. First, the existing cable force identification methods are reviewed and the influence of the damper on the cable vibration characteristics is analyzed. Second, the differential equation of cable vibration under the interference of the damper is derived, and the concept of the CDTF is defined. Then, a parameter model update method for the CDS based on the CDTF is established. Finally, the effectiveness and adaptability of this method are verified through numerical simulation and field tests, providing an effective technical means for the online monitoring and rapid field detection of the cable force in stayed cables with dampers.